The phenomenon is splendid for the eyes: waves illuminated with shimmering blue washing up on the coasts of Tasmania. This natural phenomenon is however a signal of the danger which weighs on the environment.
In Tasmania’s Preservation Bay and Cape Rocky, off the southern coast of Australia, one can admire one of the most beautiful sights in existence: the coastline dressed in shimmering blue. This is a natural phenomenon called bioluminescence and caused by Noctiluca scintillansa microscopic plankton more commonly known as the spark of the seas.
If these organisms produce this light, it is a defense mechanism chemically emitted when they are « disturbed ». In the movement of the waves, they produce this light to frighten potential predators or even to attract other species that could protect them. These algae are not toxic to humans although they can cause some irritation. If this phenomenon is beautiful, it is however very worrying.
» These apparitions are a symptom of global warming “, explains to the newspaper New Scientist Anthony Richardson, of CSIRO, Australia’s national science agency. Until twenty years ago, these organizations did not exist in this region of the world. Corn » as the Southern Ocean warms, it has become warm enough for Noctiluca to survive “, continues Anthony Richardson.
It is also the entire ecosystem that is threatened, as these organisms can upset the entire food chain. By feeding on plankton, they cause the disappearance of other algae by starving them. This change at the base of the food chain can alter the whole chain and even disturb the larger fish that people eat. This organism feeds in particular on diatoms, microalgae which also represent the food of krill, a species close to shrimp present in the region.
» This disrupts the food web to the detriment of regional fisheries and the long-term health of an ecosystem supporting a coastal population of nearly 120 million. people “, already wrote in 2014 the researchers, in the journal Nature. » As wonderful and fun as Noctiluca is, it’s also a species that could kill fish. adds today Gustaaf Hallegraeff, from the University of Tasmania.